tyager@apollo.COM (Tom Yager) (01/17/89)
I've recently been investigating the SCSI/Xenix connection for my own
purposes, and here's the scoop:
Right now, there are only two ways to run Xenix on SCSI (that I know of):
1. Tandy's 2.2.4 release
Tandy is selling a Xenix version with drivers for the Adaptec 1540
built in. An original, simple/slow driver was written by Adaptec and
sent to several Unix vendors. SCO did the 2.2 integration for Tandy
and is offering 2.3 integrated SCSI drivers to other selected hardware
OEMs.
Microport and Interactive Systems both sell Unixes which, according to
Adaptec, include drivers for their 1540.
2. Future Domain
These guys sell a variety of SCSI controllers and offer a driver
disk for Xenix versions 2.2.1 - 2.2.3. The catch: since the drivers
are on a separate disk, you have to have a running Xenix (286/386)
to load & link a new SCSI-capable kernel. The F.D. drivers are
supposed to be "custom" installable, but they wouldn't work for me
with 2.2.3 until I un-tar'ed them by hand and ran their install
script. After that, all is menu driven. After linking, it writes a
new kernel to a copy of your N1 diskette, which you then use to
install. Once installed, you can boot from your SCSI. The low-end
board I've got is only configurable for IRQ 3 (kills COM2) or
5 (kills LPT1). Their newer boards are much more versatile.
They plan to release similar drivers for 2.3 soon (3 weeks?).
The future of Xenix & SCSI:
SCO is working on their own SCSI-capable release. It will work with the
Adaptec 1540 and 1542 boards, and will (reportedly) support neat stuff
like more than two drives (finally!) and SCSI tape devices. It should
also coexist comfortably with MFM drives.
SCO is trying to get this ready to ship late January to early February.
People I spoke with there were not real optimistic that this date would
be met.
The Adaptec 1540 SCSI controller:
This is a full-length, 16-bit card. It is configurable for a broad range
of interrupt and DMA channels, and handles both asynchronous and synchronous
transfers. [note--synchronous is MUCH faster, but only certain drives are
capable of being driven this way. I understand Quantum has some nice drives
in this category...]
It is an HD only card, but the 1542 (available in the next couple of weeks)
is a combo (floppy/hard) controller which also does asynchronous DMA and
has a few other design improvements.
The 1540 has connectors for both internal and external devices. You should
be able to get one for about $350.
No drivers are included standard with the board, but an on-board ROM configures
up to two SCSI drives into your system for use under DOS. A driver disk permits
access to more than two DOS drives. The adapter revectors the BIOS disk access
routines, so it won't work with any operating system that doesn't use the BIOS
(i.e. anything but DOS). If you have an MFM drive, it will be configured as
drive C, with the SCSI as drive D.
I'm getting all these facts together for an article I'm writing about Xenix/SCSI.
If you're interested, send me mail and I'll let you know when it's coming out.
(ty)
--
+-Tom Yager, Apollo Computer R&D----------------------ARPA: tyager@apollo.com-+
| I speak only for myself. -or- tyager%maxx@m2c.m2c.org |
| "I've always said, there's nothing an agnostic can't do if he really |
+-doesn't know whether he believes in anything or not."-----------------------+